Asystole is one kind of arrhythmia which has high seriousness level. Existing patient monitors will alert for the asystole in conditions that:
1) the patient monitor has a function of asystole analysis;
2) the ECG leads are correctly connected onto the subject to be examined;
3) the asystole alarm switch is on;
4) voltage of the ECG signal detected by the patient monitor is lower than an asystole threshold (low-voltage ECG signal); and
5) duration of the low-voltage ECG signal exceeds a set threshold.
It can be seen from the conditions for asystole alarm mentioned above that any factor which can result in a low-voltage ECG signal with enough duration may result in an asystole alarm, which may lead to false alarms for asystole. Other reasons for false alarm for asystole may be:
1) that the ECG leads are not connected well, which leads to too large resistance between the electrodes and the skin of the subject to be examined;
2) that the ECG leads are connected to the subject to be examined at incorrect positions, which leads to too weak ECG signals;
3) electromagnetic interference from the surroundings, which leads to too weak ECG signals; or
4) other reasons which may result in false alarm for asystole.
Therefore, detection errors may occur during asystole detection by an existing patient monitor, thereby a false alarm may be generated. Furthermore, other arrhythmias, such as ventricular tachycardia (VT), ventricular fibrillation (VF) or the like, may also result in false alarm.